They killed Citizen Von Bek, but not before the Citizen marked them with his slow gun - for the Citizens of the Curator's Office were allowed to use forbidden weapons in the course of their duties. (Bullets from a slow gun flew on hummingbird wings, seeking wherever they might flee. Bullets from a slow gun killed by stinging with their neurotoxin barbettes, like wasps with secret police insignia. They were a terror weapon, to demonstrate the horrors of unrestricted technology.